This application claims the priority of German patent document 198 39 347.4, filed Aug. 28, 1998, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a motor vehicle ignition lock system having an electronic ignition key which can be inserted into a receptacle in an electronic ignition lock in order to exchange coded information.
Such ignition lock systems are used in motor vehicles for identifying an electronic ignition key which belongs to the electronic ignition lock. In such systems, the at least one electronic ignition key is identified by data exchange of coded operating signals between the electronic ignition lock and the electronic ignition key. The mechanical components and forms of the electronic ignition keys and the ignition locks are standardized; that is, the electronic ignition key can be inserted into any electronic ignition lock of the same type, in order to achieve more favorable manufacturing costs.
German patent document DE 33 06 863 C2 describes a generic ignition lock system, with an electronic ignition key having driver elements for a locking device, and an electronic ignition lock having a key receptacle for the electronic ignition key. Data exchange between the electronic ignition key and the electronic ignition lock takes place when the electronic ignition key is inserted into the key receptacle. The driver elements of the electronic ignition key mate with corresponding driver elements of the key receptacle for the purpose of positive engagement. An additional withdrawal protection means, which prevents withdrawal of the electronic ignition key, from the key receptacle when the key is in its turned position comes into engagement with the key only when the latter is turned, but is ineffective when the key is inserted.
It may be considered a disadvantage of this apparatus that no measures are provided to indicate that the electronic ignition lock and/or the electronic ignition key has been manipulated.
Accordingly, one object of the present invention is to provide an ignition lock system of the generic type described above, in which manipulation of the ignition lock system can be reliably detected.
This and other objects and advantages are achieved by the ignition lock system, according to the invention, in which mechanical blocking means in a key receptacle cooperate with an electronic ignition key in a blocked position of use, in such a way that the electronic ignition key and/or the key receptacle is irreversibly damaged when blocking actions of the mechanical blocking means are forcibly overcome.
In a particularly advantageous version of the invention, irreversible damage is achieved by coordination of material between the mechanical blocking means and the housing of the electronic ignition key. To this end, the mechanical blocking means or housing parts of the electronic ignition key are produced from a material which is more resistant to damage; for example, the mechanical blocking means may be produced from metal and the housing parts for the electronic ignition key from plastic. Thus, when the electronic ignition key is forcibly pulled out of the key receptacle in a blocked position of use and/or if an electronic ignition key not inserted as instructed is forcibly turned out of a blocked initial position, clearly detectable damage is caused to the key housing and/or parts of the key housing break off, so that such a manipulation can be reliably detected. So that the housing part breaks preferably at a specific point, predetermined breaking points may additionally be provided on the housing of the electronic ignition key, as indicated schematically in FIG. 1.
In an advantageous version of the invention, part of the electronic ignition key is formed as a plug and the key receptacle of the electronic ignition lock is formed as a matching plug socket. The mechanical blocking means in the key receptacle is designed to block turning and/or withdrawal of the key, and is produced from a material which is more resistant to damage, while the electronic ignition key housing part formed as a plug is produced from a material which is less resistant to damage.
The plug is inserted positively into the key receptacle when the key receptacle is in an initial position. The turn-blocking device is arranged in such a way that, in an interlocking position of the latter, if an electronic ignition key is inserted into the key receptacle in a manner other than as instructed (in particular if a plug is not inserted into the plug socket completely), a turning movement of the key receptacle within the electronic ignition lock is prevented. If an attempt is nevertheless made to overcome the blocking action of the turn-blocking means forcibly, irreversible damage to the plug of the electronic ignition key occurs due to the above-described coordination of material. If, on the other hand, an electronic ignition key is inserted as instructed (in particular if the plug is inserted into the plug socket completely), the key receptacle is released for movement.
When the key receptacle is in the initial position, the withdrawal protection device is in a release position and, outside the initial position (for example in a position of use), it blocks the electronic ignition key against withdrawal from the key receptacle. If an attempt is nevertheless made to overcome the blocking action of the withdrawal protection device forcibly, irreversible damage to the plug of the electronic ignition key occurs due to the above-described coordination of materials.
The irreversible damage depends on the nature of the act of force and may be clearly detectable traces of scratching and/or forced breaks in and/or on the plug. The turn-blocking device and the withdrawal protection device are released and secured as a result of cooperation with the external form of the plug. Due to the effect of the force of the blocking devices on the electronic ignition key, when the latter is inserted into the key receptacle of the electronic ignition lock, it is guided in a manner virtually free of play; and after being inserted as instructed, it is held in the key receptacle. The electronic ignition key is inserted correctly into the key receptacle when the plug part of the electronic ignition key is inserted completely into the plug socket of the key receptacle design. After the electronic ignition key has been inserted as instructed, the key receptacle, together with the ignition key, can be turned out of the initial position of the key receptacle into a plurality of operating positions when the electronic ignition key has been successfully identified. The operating positions of the key receptacle, together with the inserted ignition key, correspond to the various positions of a conventional ignition lock. In the operating positions, the electronic ignition key is blocked against inadvertent withdrawal from the key receptacle, by the withdrawal protection device.
The various positions of the key receptacle are detected by means of associated detectors which are designed, for example, as microswitches. In this case, the initial position of the key receptacle corresponds to the generally known ignition lock position xe2x80x9cignition offxe2x80x9d. A first operating position corresponds to the generally known ignition lock position xe2x80x9cradioxe2x80x9d, while a second operating position corresponds to the generally ignition lock position xe2x80x9cignition onxe2x80x9d, and a third operating position corresponds to the generally known ignition lock position xe2x80x9cengine startxe2x80x9d. Corresponding means are provided which automatically reset the key receptacle, together with the inserted electronic ignition key, into the second position of use again after an engine start.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.